For us there were three that we always wanted to visit - The Westin St John, the Cabo San Lucas resorts, and Harborside Atlantis.There may be several Westin/Sheraton locations that Marriott doesn't have that added value that way to some owners...
We loved the WSJ so much we bought there, we're looking forward to Cabo next year, and our kids have (thankfully) outgrown their desire to go to Atlantis.